Latest trial results aren’t a disaster in themselves. But setback feeds anxiety around company

Things are not going AstraZeneca’s way. The U.K. pharmaceuticals company said Wednesday that its cardiovascular drug Brilinta hadn’t shown significant benefits in stroke patients, compared to using aspirin. That comes less than a month after a key oncology drug also posted disappointing results in treating a rare cancer mesothelioma.

Neither is a disaster for Astra: the stock rose slightly Wednesday. But it still ups the pressure...